1. Technical Field
The present invention relates to a data interchange format for interchanging musical sequence data, a sound generating system capable of being mounted on portable terminals such as mobile phones and reproducing a musical file having the data interchange format, and a musical file creation tool capable of creating a musical file having the data interchange format from musical sequence data.
2. Related Art
There are known SMF (Standard MIDI file format) and SMAF (Synthetic Music Mobile Application Format) as data interchange formats for distributing musical sequence data to reproduce musical pieces using a sound generator.
The SMF is a data format for saving musical performance information and interchanging data. When an SMF file is created based on the GM (General MIDI) standard, the file can be reproduced to a certain degree of quality according to a timbre map using musical instrument timbres provided for the sound generator.
The SMAF is a data format specification for representing multimedia contents on mobile terminals (see Online document “SMAF specification outline” by YAMAHA CORPORATION retrieved on Jun. 30, 2004, at the Internet address <URL:http//smaf-yamaha.com/jp/what/smaf_spec.html>).
Further, Patent document, Japanese Patent Unexamined Publication No. 2003-22072, discloses the musical file (SMAF file) with timbre data. For FM sound generators, timbre data (timbre parameters) signifies parameters to specify an FM operation algorithm. For waveform memory (WT) sound generators, timbre data signifies timbre waveform data and the like.
Depending on models of sound generators, the same musical instrument generates different timbre overtones and sound pressures. If an SMF file is created in accordance with the GM timbre map, there may be a case where the musical piece cannot be reproduced as faithfully as producer's intention depending on types and models of sound generators used for the reproduction.
There may be a case of reproducing the musical file (SMAF file) with timbre data as described in the above-mentioned patent document on a sound generator that is incompatible with the timbre data contained in the SMAF file. In this case, the sound generator reproduces equivalent timbres using its own timbre data while ignoring the timbre data attached to the file. Likewise the case of SMF files, the sound generator reproduces the file using its own default timbres corresponding to program change numbers (timbre numbers) included in program change messages.
Presently, some portable terminals use sound generators incompatible with the timbre data contained in the SMAF file. Other portable terminals use sound generators compatible with the timbre data contained in the SMAF file.
FIG. 8 shows a manner by which a general sound generator, SMAF-incompatible sound generating system, reproduces a music content of SMAF file containing timbre data.
According to the example shown in FIG. 8, the content is an SMAF file containing a specific piano timbre corresponding to program change number #1 and a specific guitar timbre corresponding to program change number #25. When processing this SMAF file, the SMAF-incompatible sound generating system cannot process the attached timbres. The system reproduces equivalent or substitute timbres such as general piano timbre and general guitar timbre stored in the system ROM based only on the program change numbers.
Regarding the piano corresponding to program change number #1, for example, the SMAF file originally contains the timbre data representing the specific piano timbre tuned to the musical piece's atmosphere. It is not proper to use any generic piano timbres in place of the specific piano timbre tuned to the musical piece's atmosphere. Nevertheless, the SMAF-incompatible sound generating system generates substitute timbres. Accordingly, the timber reproduced by the SMAF-incompatible sound generator becomes different from the original timbre that the producer has intended.
Nevertheless, a user still listens to nothing but the reproduced piano sound and may not notice a delicate difference from the original piano sound. The user misunderstands the grade of the musical file, degrading its true value.